Patent GB-634708-A (GB)
Title: Improvements in voltage or current control systems
IPC: G05F1/52
Filed: 1946-07-02
Abstract: 634,708. Automatic voltage and current control systems. WESTERN ELECTRIC CO., Inc. July 2, 1946, No. 19769. Convention date, July 4, 1945. [Class 38 (iv)] A control voltage is applied to the input of a D.C. amplifier the output of which controls the amplitude of an alternating current which, after further amplification, is rectified to produce a controllable power source of direct current or voltage. As shown, a magnetron or other high frequency generator under test, 60, is supplied from an A.C. source 90 through a rectifier 80 and a pulser 70. To the output of rectifier 80 is added a D.C. voltage between conductor 105 and earth which is varied automatically to maintain constant the average anode current or voltage of the magnetron during test. Current.-With switches SW1, SW2, SW6, SW7, SW8, SW9 in their left-hand positions there is included in the anode circuit of the magnetron a resistance-condenser network R1- R6, C1, the time-constant of which is such that a D.C. voltage, dependent on the average anode current, is applied through switch SW2 to a two-stage direct-coupled D.C. amplifier, including triodes V1, V2, the output of which is applied to one grid, 101, of a hexode modulator valve V3. A constant A.C. voltage derived from an A.C. source 50 through a transformer T5 is applied to another grid 102 of the modulator valve so that the amplitude of A.C. output of a transformer T6 is dependent on the average anode current. This output is applied to a phase-inverting double-triode valve V4 driving parallel push-pull tetrode amplifier valves V9-V12 the output of which supplies, through a variable ratio transformer T7, a voltage-doubler rectifier V13, V14 producing the D.C. voltage between conductor 105 and earth. A meter M1 indicates this voltage and a meter M3 indicates average anode current. A diode V20 maintains the circuit between rectifier 80 and pulser 70 if automatic control is inoperative. When it is undesirable that a resistance-condenser network be connected between anode and earth, switches SW1, SW2, SW6, SW7, SW8, SW9 are moved to their central positions to connect it between the positive terminal of the pulser and earth. A small resistance R44 may then be inserted between anode and earth by the operation of switch SW10 to provide an output for a cathoderay oscilloscope. Voltage.-With switches SW1, SW2, SW6, SW7, SW8, SW9 in their right-hand positions the resistance-condenser network in series with the magnetron is disconnected and a potential divider R35, R36 supplying, through a rectifier V17, another R-C network R7, R38, R8, R37, C4 is connected in parallel with the magnetron. The D.C. voltage obtained from this R-C network is dependent on the average anode-cathode voltage of the magnetron and is applied to the D.C. amplifier to stabilize anode voltage. A valve voltmeter, including a triode V18 and a meter M2 indicates this voltage. H.T. and L.T. supplies to the valves involve transformers T1 and T2, rectifiers V15 and V16 and neon stabilizers V5-V8 and V19. Specifications 396,684 and 444,058 are referred to.